Not a bad guess, honestly. Pretty sure some past outages have been due to new services (such as the new Search), either due to bugs or potential security issues.
I'm not trying to blame Github though, they're awesome!
Github was down so I took a break at work to read some Hacker News. "Ooh 3D file diffs, cool!" Click the link to read about the new feature, and dammit it's down too because the blog is hosted on github.com!
I'm not trying to blame Github though, they're awesome!